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ORBi^lu

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	References of "Regesch, David 50002916" in Showing results 1 to 17 of 17 1 Deliberate and Accidental Gas-Phase Alkali Doping of Chalcogenide Semiconductors: Cu(In,Ga)Se2 Colombara, Diego ; Berner, Ulrich; Ciccioli, Andrea et al in Scientific Reports (2017), 7 Alkali metal doping is essential to achieve highly efficient energy conversion in Cu(In,Ga)Se2 (CIGSe) solar cells. Doping is normally achieved through solid state reactions, but recent observations of ... [more ▼] Alkali metal doping is essential to achieve highly efficient energy conversion in Cu(In,Ga)Se2 (CIGSe) solar cells. Doping is normally achieved through solid state reactions, but recent observations of gas phase alkali transport in the kesterite sulfide (Cu2ZnSnS4) system (re)open the way to a novel gas-phase doping strategy. However, the current understanding of gas-phase alkali transport is very limited. This work (i) shows that CIGSe device efficiency can be improved from 2% to 8% by gas-phase sodium incorporation alone, (ii) identifies the most likely routes for gas-phase alkali transport based on mass spectrometric studies, (iii) provides thermochemical computations to rationalize the observations and (iv) critically discusses the subject literature with the aim to better understand the chemical basis of the phenomenon. These results suggest that accidental alkali metal doping occurs all the time, that a controlled vapor pressure of alkali metal could be applied during growth to dope the semiconductor, and that it may have to be accounted for during the currently used solid state doping routes. It is concluded that alkali gas-phase transport occurs through a plurality of routes and cannot be attributed to one single source. [less ▲] Detailed reference viewed: 303 (14 UL) Revisiting radiative deep-level transitions in CuGaSe2 by photoluminescence Spindler, Conrad ; Siebentritt, Susanne ; Regesch, David in Applied Physics Letters (2016), 109 Detailed reference viewed: 244 (25 UL) What is the band gap of kesterite? Siebentritt, Susanne ; Rey, Germain ; Finger, Ashley et al in Solar Energy Materials and Solar Cells (2015) Detailed reference viewed: 270 (8 UL) The Importance of Se Partial Pressure in the Laser Annealing of CuInSe2 Electrodeposited Precursors Meadows, Helen ; Regesch, David ; Schuler, Thomas et al Scientific Conference (2015) Detailed reference viewed: 238 (4 UL) Prediction of photovoltaic p-n device short circuit current by photoelectrochemical analysis of p-type CIGSe films Colombara, Diego ; Crossay, Alexandre ; Regesch, David et al in Electrochemistry Communications (2014), 48 The quality control of individual semiconductor thin films during fabrication of multiple layers is important for industry and academia. The ultimate aim of this research is to predict the efficiency of p ... [more ▼] The quality control of individual semiconductor thin films during fabrication of multiple layers is important for industry and academia. The ultimate aim of this research is to predict the efficiency of p-–n junction solar cells by photoelectrochemical analysis of the bare p-type semiconductor. A linear correlation between the photocurrent measured electrochemically on Cu(In,Ga)Se2 absorber layers through a Eu3+ electrolyte junction and short circuit current and efficiency of the corresponding solid state devices is found. However, the correlation is complicated by pronounced recombination at the semiconductor/electrolyte interface, while the solid state interface behaves more ideally. [less ▲] Detailed reference viewed: 224 (9 UL) Photoluminescence and solar cell studies of chalcopyrites - comparison of Cu-rich vs. Cu-poor and polycrystalline vs. epitaxial material Regesch, David Doctoral thesis (2014) The quasi-Fermi level splitting (qFls) in a solar cell absorber limits the maximum achievable open circuit voltage of the final device. A calibrated photoluminescence set-up allows the determination of ... [more ▼] The quasi-Fermi level splitting (qFls) in a solar cell absorber limits the maximum achievable open circuit voltage of the final device. A calibrated photoluminescence set-up allows the determination of the qFls at room temperature under conditions equivalent to the illumination from the sun. In this work the qFls is used as an indicator for the quality of epitaxial and polycrystalline thin CuInSe2 films with different compositions. It is shown, that the epitaxial material exhibits improved optoelectronic quality noticeable in the higher qFls (50-100meV) when compared to the polycrystalline counterpart. Furthermore, a dependency on the Cu/In ratio is noticed: In Cu poor material (Cu/In<1) the qFls increases with an increasing Cu concentration and levels off for the absorbers grown under Cu-rich conditions (Cu/In>1). The difference between absorbers grown under Cu-poor and Cu-rich conditions is found to be in the order of 150meV. Additionally, the compositional dependence of the Urbach energy and of the band gap energy has been evaluated from the PL spectra at room temperature. Slightly higher bandgaps and lower Urbach energies have been found for the Cu rich material compared to the Cu poor absorbers. The time dependent change of the qFls of bare CuInSe2 absorbers exposed to air is presented and shows for Cu-poor absorbers a pronounced and for Cu-rich material a slower degradation. It is shown, that a chemical etching in potassium cyanide refreshes the degraded material to an extent comparable to freshly grown samples, and that the deposition of a CdS buffer layer passivates the surface. Epitaxial Cu(In,Ga)Se2 is grown by means of metal organic vapour phase epitaxy and used to produce epitaxial solar cells. A maximum power conversion efficiency of 6.7% has been achieved. All solar cells suffer from dominant interface recombination processes which limit the device performance. The critical interface is between the absorber layer and the CdS buffer and related to the high gallium content. [less ▲] Detailed reference viewed: 271 (38 UL) Direct Evaluation of Defect Distributions From Admittance Spectroscopy Weiss, Thomas ; Redinger, Alex ; Regesch, David et al in IEEE JOURNAL OF PHOTOVOLTAICS (2014), 4 Detailed reference viewed: 202 (12 UL) Single Second Laser Annealed CuInSe2 Semiconductors from Electrodeposited Precursors as Absorber Layers for Solar Cells Meadows, Helen ; Bathia, Ashish; Depredurand, Valérie et al in Journal of Physical Chemistry. C, Nanomaterials and interfaces (2014), 118 (3) Detailed reference viewed: 219 (13 UL) Tuning the gallium content of metal precursors for Cu(In,Ga)Se2 thin film solar cells by electrodeposition from a deep eutectic solvent Malaquias, Joao Corujo Branco ; Regesch, David ; Dale, Phillip et al in Physical Chemistry Chemical Physics (2014), 16 Detailed reference viewed: 164 (8 UL) Epitaxial Cu2ZnSnSe4 thin films and devices Redinger, Alex ; Groiss, Heiko; Sendler, Jan et al in Thin Solid Films (2014) Detailed reference viewed: 197 (8 UL) CuInSe2 semiconductor formation by laser annealing Meadows, Helen ; Regesch, David ; Thevenin, Maxime et al in Thin Solid Films (2014) Detailed reference viewed: 154 (2 UL) The influence of Se pressure on the electronic properties of CuInSe2 grown under Cu-excess Depredurand, Valérie ; Bertram, Tobias ; Regesch, David et al in Applied Physics Letters (2014), 105 Detailed reference viewed: 183 (11 UL) Composition dependent characterization of copper indium diselenide thin film solar cells synthesized from electrodeposited binary selenide precursor stacks Fischer, Johannes; Larsen, Jes K. ; Guillot, Jerôme et al in Solar Energy Materials and Solar Cells (2014), 126 Detailed reference viewed: 203 (9 UL) Why do we make Cu(In,Ga)Se2 solar cells non-stoichiometric? Siebentritt, Susanne ; Gütay, Levent ; Regesch, David et al in Solar Energy Materials and Solar Cells (2013) Detailed reference viewed: 233 (5 UL) Degradation and passivation of CuInSe2 Regesch, David ; Gütay, Levent ; Larsen, Jes K. et al in Applied Physics Letters (2012), 101 Detailed reference viewed: 211 (10 UL) Feedback mechanism for the stability of the band gap of CuInSe2 Gutay, Levent ; Regesch, David ; Larsen, Jes K. et al in Physical Review (2012), 86 Detailed reference viewed: 229 (10 UL) Influence of copper excess on the absorber quality of CulnSe2 Gütay, Levent ; Regesch, David ; Larsen, Jes K. et al in Applied Physics Letters (2011), 99(151912), 1519121-15191123 Detailed reference viewed: 126 (17 UL) 1

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